Makes Adjusting Valve EasierUnique All-in-e Design Positively Tights Jam Nut While Preventing The Stud Movement Often Encountered When Using 2 Separate Tools7 1/2" Handle Provides Necessary Torque For Loosening Jam NutsWindow Allows Viewing Of Screwdriver Blade Position For Easier EngagementDesigned For Toyota, Honda, Nissan, Mazda And Mitsubishi Engines With 10mm Jam Nut And Slotted Valve Adjusting Stud